GeometrySet: Add new GreasePencilComponent

This is mostly boilerplate code to add a new `GeometryComponent` as well as making sure
the new `GeometryComponent::Type` is handled in all the `switch` statements.

Pull Request: https://projects.blender.org/blender/blender/pulls/110457

source/blender/blenkernel/BKE_geometry_set.hh

@@ -22,10 +22,11 @@ struct Curve;
 struct Mesh;
 struct PointCloud;
 struct Volume;
+struct GreasePencil;
 
 namespace blender::bke {
 
-#define GEO_COMPONENT_TYPE_ENUM_SIZE 6
+#define GEO_COMPONENT_TYPE_ENUM_SIZE 7
 
 enum class GeometryOwnershipType {
   /* The geometry is owned. This implies that it can be changed. */
@@ -63,6 +64,7 @@ class GeometryComponent : public ImplicitSharingMixin {
     Volume = 3,
     Curve = 4,
     Edit = 5,
+    GreasePencil = 6,
   };
 
  private:
@@ -120,6 +122,7 @@ inline constexpr bool is_geometry_component_v = std::is_base_of_v<GeometryCompon
  *  - #PointCloudComponent
  *  - #InstancesComponent
  *  - #VolumeComponent
+ *  - #GreasePencilComponent
  *
  * Copying a geometry set is a relatively cheap operation, because it does not copy the referenced
  * geometry components, so #GeometrySet can often be passed or moved by value.
@@ -266,6 +269,11 @@ struct GeometrySet {
    */
   static GeometrySet create_with_instances(
       Instances *instances, GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
+  /**
+   * Create a new geometry set that only contains the given Grease Pencil data.
+   */
+  static GeometrySet create_with_grease_pencil(
+      GreasePencil *grease_pencil, GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
 
   /* Utility methods for access. */
   /**
@@ -292,6 +300,10 @@ struct GeometrySet {
    * Returns true when the geometry set has any data that is not an instance.
    */
   bool has_realized_data() const;
+  /**
+   * Returns true when the geometry set has a Grease Pencil component that has grease pencil data.
+   */
+  bool has_grease_pencil() const;
   /**
    * Return true if the geometry set has any component that isn't empty.
    */
@@ -321,6 +333,10 @@ struct GeometrySet {
    * Returns read-only curve edit hints or null.
    */
   const CurvesEditHints *get_curve_edit_hints_for_read() const;
+  /**
+   * Returns a read-only Grease Pencil data-block or null.
+   */
+  const GreasePencil *get_grease_pencil_for_read() const;
 
   /**
    * Returns a mutable mesh or null. No ownership is transferred.
@@ -346,6 +362,10 @@ struct GeometrySet {
    * Returns mutable curve edit hints or null.
    */
   CurvesEditHints *get_curve_edit_hints_for_write();
+  /**
+   * Returns a mutable Grease Pencil data-block or null. No ownership is transferred.
+   */
+  GreasePencil *get_grease_pencil_for_write();
 
   /* Utility methods for replacement. */
   /**
@@ -372,6 +392,11 @@ struct GeometrySet {
    */
   void replace_instances(Instances *instances,
                          GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
+  /**
+   * Clear the existing Grease Pencil data-block and replace it with the given one.
+   */
+  void replace_grease_pencil(GreasePencil *grease_pencil,
+                             GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
 
  private:
   /**
@@ -655,4 +680,43 @@ class GeometryComponentEditData final : public GeometryComponent {
   static constexpr inline GeometryComponent::Type static_type = GeometryComponent::Type::Edit;
 };
 
+/**
+ * A geometry component that stores #GreasePencil data.
+ * This component does not implement an attribute API, because the #GreasePencil data itself does
+ * not store any attributes, only the individual drawings within it.
+ */
+class GreasePencilComponent : public GeometryComponent {
+ private:
+  GreasePencil *grease_pencil_ = nullptr;
+  GeometryOwnershipType ownership_ = GeometryOwnershipType::Owned;
+
+ public:
+  GreasePencilComponent();
+  ~GreasePencilComponent();
+  GeometryComponent *copy() const override;
+
+  void clear() override;
+  bool has_grease_pencil() const;
+  /**
+   * Clear the component and replace it with the new \a grease_pencil data.
+   */
+  void replace(GreasePencil *grease_pencil,
+               GeometryOwnershipType ownership = GeometryOwnershipType::Owned);
+  /**
+   * Return the Grease Pencil data and clear the component. The caller takes over responsibility
+   * for freeing the Grease Pencil data (if the component was responsible before).
+   */
+  GreasePencil *release();
+
+  const GreasePencil *get_for_read() const;
+  GreasePencil *get_for_write();
+
+  bool is_empty() const final;
+
+  bool owns_direct_data() const override;
+  void ensure_owns_direct_data() override;
+
+  static constexpr inline GeometryComponent::Type static_type = Type::GreasePencil;
+};
+
 }  // namespace blender::bke

source/blender/blenkernel/BKE_grease_pencil.hh

@@ -542,6 +542,7 @@ inline bool GreasePencil::has_active_layer() const
 
 void *BKE_grease_pencil_add(Main *bmain, const char *name);
 GreasePencil *BKE_grease_pencil_new_nomain();
+GreasePencil *BKE_grease_pencil_copy_for_eval(const GreasePencil *grease_pencil_src);
 BoundBox *BKE_grease_pencil_boundbox_get(Object *ob);
 void BKE_grease_pencil_data_update(struct Depsgraph *depsgraph,
                                    struct Scene *scene,

source/blender/blenkernel/CMakeLists.txt

@@ -133,6 +133,7 @@ set(SRC
   intern/freestyle.cc
   intern/geometry_component_curves.cc
   intern/geometry_component_edit_data.cc
+  intern/geometry_component_grease_pencil.cc
   intern/geometry_component_instances.cc
   intern/geometry_component_mesh.cc
   intern/geometry_component_pointcloud.cc

source/blender/blenkernel/intern/geometry_component_grease_pencil.cc

@@ -0,0 +1,98 @@
+/* SPDX-FileCopyrightText: 2023 Blender Foundation
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_geometry_set.hh"
+#include "BKE_grease_pencil.hh"
+#include "BKE_lib_id.h"
+
+namespace blender::bke {
+
+/* -------------------------------------------------------------------- */
+/** \name Geometry Component Implementation
+ * \{ */
+
+GreasePencilComponent::GreasePencilComponent() : GeometryComponent(Type::GreasePencil) {}
+
+GreasePencilComponent::~GreasePencilComponent()
+{
+  this->clear();
+}
+
+GeometryComponent *GreasePencilComponent::copy() const
+{
+  GreasePencilComponent *new_component = new GreasePencilComponent();
+  if (grease_pencil_ != nullptr) {
+    new_component->grease_pencil_ = BKE_grease_pencil_copy_for_eval(grease_pencil_);
+    new_component->ownership_ = GeometryOwnershipType::Owned;
+  }
+  return new_component;
+}
+
+void GreasePencilComponent::clear()
+{
+  BLI_assert(this->is_mutable() || this->is_expired());
+  if (grease_pencil_ != nullptr) {
+    if (ownership_ == GeometryOwnershipType::Owned) {
+      BKE_id_free(nullptr, grease_pencil_);
+    }
+    grease_pencil_ = nullptr;
+  }
+}
+
+bool GreasePencilComponent::has_grease_pencil() const
+{
+  return grease_pencil_ != nullptr;
+}
+
+void GreasePencilComponent::replace(GreasePencil *grease_pencil, GeometryOwnershipType ownership)
+{
+  BLI_assert(this->is_mutable());
+  this->clear();
+  grease_pencil_ = grease_pencil;
+  ownership_ = ownership;
+}
+
+GreasePencil *GreasePencilComponent::release()
+{
+  BLI_assert(this->is_mutable());
+  GreasePencil *grease_pencil = grease_pencil_;
+  grease_pencil_ = nullptr;
+  return grease_pencil;
+}
+
+const GreasePencil *GreasePencilComponent::get_for_read() const
+{
+  return grease_pencil_;
+}
+
+GreasePencil *GreasePencilComponent::get_for_write()
+{
+  BLI_assert(this->is_mutable());
+  if (ownership_ == GeometryOwnershipType::ReadOnly) {
+    grease_pencil_ = BKE_grease_pencil_copy_for_eval(grease_pencil_);
+    ownership_ = GeometryOwnershipType::Owned;
+  }
+  return grease_pencil_;
+}
+
+bool GreasePencilComponent::is_empty() const
+{
+  return grease_pencil_ == nullptr;
+}
+
+bool GreasePencilComponent::owns_direct_data() const
+{
+  return ownership_ == GeometryOwnershipType::Owned;
+}
+
+void GreasePencilComponent::ensure_owns_direct_data()
+{
+  BLI_assert(this->is_mutable());
+  if (ownership_ != GeometryOwnershipType::Owned) {
+    grease_pencil_ = BKE_grease_pencil_copy_for_eval(grease_pencil_);
+    ownership_ = GeometryOwnershipType::Owned;
+  }
+}
+
+}  // namespace blender::bke

source/blender/blenkernel/intern/geometry_fields.cc

@@ -76,6 +76,7 @@ GeometryFieldContext::GeometryFieldContext(const GeometryComponent &component,
     }
     case GeometryComponent::Type::Volume:
     case GeometryComponent::Type::Edit:
+    case GeometryComponent::Type::GreasePencil:
       BLI_assert_unreachable();
       break;
   }

source/blender/blenkernel/intern/geometry_set.cc

@@ -51,6 +51,8 @@ GeometryComponentPtr GeometryComponent::create(Type component_type)
       return new CurveComponent();
     case Type::Edit:
       return new GeometryComponentEditData();
+    case Type::GreasePencil:
+      return new GreasePencilComponent();
   }
   BLI_assert_unreachable();
   return {};
@@ -344,6 +346,12 @@ const CurvesEditHints *GeometrySet::get_curve_edit_hints_for_read() const
   return (component == nullptr) ? nullptr : component->curves_edit_hints_.get();
 }
 
+const GreasePencil *GeometrySet::get_grease_pencil_for_read() const
+{
+  const GreasePencilComponent *component = this->get_component_for_read<GreasePencilComponent>();
+  return (component == nullptr) ? nullptr : component->get_for_read();
+}
+
 bool GeometrySet::has_pointcloud() const
 {
   const PointCloudComponent *component = this->get_component_for_read<PointCloudComponent>();
@@ -381,10 +389,16 @@ bool GeometrySet::has_realized_data() const
   return false;
 }
 
+bool GeometrySet::has_grease_pencil() const
+{
+  const GreasePencilComponent *component = this->get_component_for_read<GreasePencilComponent>();
+  return component != nullptr && component->has_grease_pencil();
+}
+
 bool GeometrySet::is_empty() const
 {
   return !(this->has_mesh() || this->has_curves() || this->has_pointcloud() ||
-           this->has_volume() || this->has_instances());
+           this->has_volume() || this->has_instances() || this->has_grease_pencil());
 }
 
 GeometrySet GeometrySet::create_with_mesh(Mesh *mesh, GeometryOwnershipType ownership)
@@ -424,6 +438,14 @@ GeometrySet GeometrySet::create_with_instances(Instances *instances,
   return geometry_set;
 }
 
+GeometrySet GeometrySet::create_with_grease_pencil(GreasePencil *grease_pencil,
+                                                   GeometryOwnershipType ownership)
+{
+  GeometrySet geometry_set;
+  geometry_set.replace_grease_pencil(grease_pencil, ownership);
+  return geometry_set;
+}
+
 void GeometrySet::replace_mesh(Mesh *mesh, GeometryOwnershipType ownership)
 {
   if (mesh == nullptr) {
@@ -494,6 +516,21 @@ void GeometrySet::replace_volume(Volume *volume, GeometryOwnershipType ownership
   component.replace(volume, ownership);
 }
 
+void GeometrySet::replace_grease_pencil(GreasePencil *grease_pencil,
+                                        GeometryOwnershipType ownership)
+{
+  if (grease_pencil == nullptr) {
+    this->remove<GreasePencilComponent>();
+    return;
+  }
+  if (grease_pencil == this->get_grease_pencil_for_read()) {
+    return;
+  }
+  this->remove<GreasePencilComponent>();
+  GreasePencilComponent &component = this->get_component_for_write<GreasePencilComponent>();
+  component.replace(grease_pencil, ownership);
+}
+
 Mesh *GeometrySet::get_mesh_for_write()
 {
   MeshComponent *component = this->get_component_ptr<MeshComponent>();
@@ -534,6 +571,12 @@ CurvesEditHints *GeometrySet::get_curve_edit_hints_for_write()
   return component.curves_edit_hints_.get();
 }
 
+GreasePencil *GeometrySet::get_grease_pencil_for_write()
+{
+  GreasePencilComponent *component = this->get_component_ptr<GreasePencilComponent>();
+  return component == nullptr ? nullptr : component->get_for_write();
+}
+
 void GeometrySet::attribute_foreach(const Span<GeometryComponent::Type> component_types,
                                     const bool include_instances,
                                     const AttributeForeachCallback callback) const
@@ -709,6 +752,9 @@ bool object_has_geometry_set_instances(const Object &object)
         break;
       case GeometryComponent::Type::Edit:
         break;
+      case GeometryComponent::Type::GreasePencil:
+        is_instance = object.type != OB_GREASE_PENCIL;
+        break;
     }
     if (is_instance) {
       return true;

source/blender/blenkernel/intern/grease_pencil.cc

@@ -1044,6 +1044,12 @@ GreasePencil *BKE_grease_pencil_new_nomain()
   return grease_pencil;
 }
 
+GreasePencil *BKE_grease_pencil_copy_for_eval(const GreasePencil *grease_pencil_src)
+{
+  return reinterpret_cast<GreasePencil *>(
+      BKE_id_copy_ex(nullptr, &grease_pencil_src->id, nullptr, LIB_ID_COPY_LOCALIZE));
+}
+
 BoundBox *BKE_grease_pencil_boundbox_get(Object *ob)
 {
   using namespace blender;

source/blender/editors/space_node/node_draw.cc

@@ -985,6 +985,10 @@ static void create_inspection_string_for_geometry_info(const geo_log::GeometryIn
         }
         break;
       }
+      case bke::GeometryComponent::Type::GreasePencil: {
+        /* TODO. Do nothing for now. */
+        break;
+      }
     }
     if (type != component_types.last()) {
       ss << ".\n";
@@ -1038,6 +1042,10 @@ static void create_inspection_string_for_geometry_socket(std::stringstream &ss,
       case bke::GeometryComponent::Type::Edit: {
         break;
       }
+      case bke::GeometryComponent::Type::GreasePencil: {
+        ss << TIP_("Grease Pencil");
+        break;
+      }
     }
     if (type != supported_types.last()) {
       ss << ", ";

source/blender/geometry/intern/realize_instances.cc

@@ -627,6 +627,10 @@ static void gather_realize_tasks_recursive(GatherTasksInfo &gather_info,
         }
         break;
       }
+      case bke::GeometryComponent::Type::GreasePencil: {
+        /* TODO. Do nothing for now. */
+        break;
+      }
     }
   }
 }

source/blender/nodes/intern/geometry_nodes_log.cc

@@ -126,6 +126,10 @@ GeometryInfoLog::GeometryInfoLog(const bke::GeometrySet &geometry_set)
       case bke::GeometryComponent::Type::Volume: {
         break;
       }
+      case bke::GeometryComponent::Type::GreasePencil: {
+        /* TODO. Do nothing for now. */
+        break;
+      }
     }
   }
 }

source/blender/nodes/intern/node_geometry_exec.cc

@@ -96,6 +96,10 @@ void GeoNodeExecParams::check_input_geometry_set(StringRef identifier,
       case GeometryComponent::Type::Edit: {
         continue;
       }
+      case GeometryComponent::Type::GreasePencil: {
+        message += TIP_("Grease Pencil");
+        break;
+      }
     }
     this->error_message_add(NodeWarningType::Info, std::move(message));
   }